Method and apparatus for mixing materials in a bag with a movable plunger

Abstract

Building materials such as concrete, mortar and plaster are placed in a bag which is suspended in a bottomless drum. A handle is used to move a plunger up-and-down through the bottom of the drum such that the plunger repeatedly moves part of the bag upwardly through the materials contained in the bag to cause mixing thereof. The drum is rotationally indexed with reciprocal movements of the plunger, which also moves laterally. The plunger has an interchangeable head having a leading face which is inclined with respect to the direction of lateral movement on the upward stroke, and at least one inclined downwardly-facing facet.

What is claimed is:  
     
       1. A method of preparing a homogeneous mixture of two or more materials which comprises: 
       placing the materials to be mixed into a bag ( 12 ) formed of flexible material;  
       suspending three bag from an upper region thereof above a plunger ( 4 ); and  
       producing relative up-and-down movement between the bag and plunger such that the plunger repeatedly moves part of the bag upwardly through the materials contained in the bag to cause mixing thereof;  
       characterised by 
       relative lateral movement (B) between the plunger and the bag during such relative up-and-down movement, and by relative rotational indexing between the plunger and the bag with reciprocation of the plunger.  
     
     
       2. A method according to  claim 1 , in which the amount of said relative up-and-down movement is sufficient to cause the bag to protrude above the mean surface level of the bulk of the material being mixed. 
     
     
       3. Mixing apparatus comprising: 
       holding means ( 31 ) for suspending a bag ( 12 ) from an upper region of said bag;  
       a plunger ( 4 ) located below said holding means, said plunger having a head ( 22 ) with a leading face ( 25 );  
       means ( 6 ) for producing relative up-and-down movement between said holding means and said plunger such that: said plunger moves up-and-down whilst said holding means remains stationary; relative lateral movement (B) occurs between the plunger and the bag during such relative up-and-down movement; said plunger moves laterally on its upward stroke with said leading face ( 25 ) inclined with respect to the direction (C) of said lateral movement; and, when a bag containing materials to be mixed is suspended from said holding means, the plunger repeatedly moves part of the bag upwardly through the materials contained in the bag to cause mixing thereof; and  
       means ( 15 ) for producing relative rotational indexing between the plunger and the bag with reciprocation of the plunger.  
     
     
       4. Mixing apparatus according to  claim 3 , in which said plunger head ( 22 ) has at least one inclined downwardly-directed facet ( 26 ). 
     
     
       5. Mixing apparatus according to  claim 3 , in which the plunger is provided with interchangeable heads.